Answer: Go outside on the catwalk and look for the 2 posts. Look down over the ledge and wait for a pipe to extend. Drop down on it and, when it retracts, go in it and you'll be under the red room. Now you can stop the process in the red room and get on the carts with impunity.

Umm... what catwalk? Could some one provide a screen shot of the cat walk and two posts? Thanks.